Holding arrangement for motor saws

ABSTRACT

A holding arrangement for a motor operated chain saw which includes a handle near the front end of the motor housing and a support for engaging the lower arm near the rear end of the motor housing. The support may be ring-like or yoke-like and the support and handle are carried by a member which is connected to the motor housing by resilient vibration damping elements.

United States Patent 1 Heermann Nov. 20, 1973 i 22 Filed:

[ HOLDING ARRA NGEMENT FOR MOTOR SAWS Inventor: Richard Heermann,I-lebsack,

Germany [73] Assignee: Andreas StihlMaschinent'abrik,

Neustadt near Waiblingen, Germany Oct. 14, 1970 211 Appl. No.: 80,578

[30] Foreign Application Priority Data Oct. 16, 1969 Germany P 19 52 066.2

[52] US. Cl 30/382, 173/162, 30/383 [51] Int. Cl 1327b 17/02 [58] Field of Search 143/32 R, 32 K, 43 H;

[56] References Cited UNITED STATES PATENTS 2,504,880 4/1950 Rittenhouse 143/43 H 3,525,373 8/1970 Kobayashi 143/32 R 3,651,839 3/1972 Stihl et a1.. 143/32 R 3,530,909 9/1970 Scharpf 143/32 R 3,542,095 11/1970 Frederickson 143/32 R Primary ExaminerDonald R. Schran Attorney-Walter Becker [5 7] ABSTRACT 15 Claims, 7 Drawing Figures PATENTEDuavao 1975 3,772,784

' sum 2 or 2 1 HOLDING ARRANGEMENT FOR MOTOR SAWS I The present invention concerns a holding device for motor saws, especially motor chain saws, with at least one handle part adapted to be grasped by a hand and with a supporting part behind said handle part.

With heretofore known holding arrangements of the above mentioned general type, the rear handle part is likewise in the shape of a handle, i.e. a handle to be grasped by a hand, so that when using the motor saw it is necessary to grasp each handle individually with one hand which means that no hand is free for any other manipulations.

During a number of working operations to be carried out with the motor saw, it is desirable to have one hand free, for instance for pushing aside branches, for holding the wood, for exerting a pressure upon the wood to be cut, and the like. There are, of course, known motor saws which have an upper handle part extending rearwardly similar to the handle of an iron for ironing cloths, by means of which sawing operations can be carried out when the saw is held with one hand only. In such an instance, however, the motor saw is held at one 2, single place only so that the carrying and guiding of the of the operator. This is particularly true, for instance,

when during the sawing off of tree branches in orchards, the operator standing on a ladder has with one hand to hold on to the tree, some branches or the ladder.

It is, therefore, an object of the present invention to provide a holding device of the above mentioned type in such a way that while being of simple construction, the motor saw can safely be used while being held with one hand only.

This object and other objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawings, in which:

FIG. 1 illustrates a side view of a motor saw provided with a holding device according to the invention.

FIG. 2 is a top view of the motor saw of FIG. ll.

FIG. 3 shows the motor saw of FIG. 1 as seen from the left-hand side of FIG. 1.

FIG. 4 diagrammatically illustrates a further embodiment of a motor saw with a holding device according to the invention.

FIG. 5 shows a portion of the motor saw of FIG. 4 but with the holding device in a differently adjusted position.

FIG. 6 illustrates the holding device in a position which differs from that of FIG. 5. FIG. 7 represents a top view of a modified motor saw according to the invention.

The motor saw, especially motor chain saw, according to the present invention which has at least one handle part to be grasped by a hand and a holding part located behind said handle part, is characterized primarily in that the holding or supporting part located behind the handle part is designed as support with an engaging or supporting surface for the lower part of the arm of the operator. When the holding device of this design is grasped by the hand and when the arm engages the engaging or supporting surface of the holding part, it will be appreciated that while using only one arm, it is possible to hold the motor saw at two places spaced from each other and located one behind the other. In this way the motor saw can during all sawing operations and in all cutting directions be guided and held in a satisfactory manner while the free hand of the operator is available for whatever operation is necessary. The holding device according to the present invention is particularly suitable for so-called small motor saws which have a low weight and therefore do not require great operating forces on the part of the operator.

Expediently, the supporting surface for the lower part of the arm defines a passage the central axis of which extends in approximately the longitudinal direction of the motor saw and is in alignment with the handle part so that when the lower arm occupies a position in which its longitudinal extension is in the direction of the longitudinal axis of the motor saw, the lower arm resting in said passage permits a safe and proper handling of the saw.

It is also possible to form said passage by supporting members which surround the lower arm and which are spaced from each other while being located adjacent to each other. It is, however, particularly advantageous to form the arm support by a ring which is at least approximately closed so that a uniform support of the arm will be assured in all directions.

It is also possible to make the members defining the passage, i. e. the arm support, flexible or slightly elastic in a direction transverse and/or parallel to the central axis of said passage. The supporting member may, for instance, be designed in the form of a band loop so that a corresponding movability of the arm support is obtained. It is particularly advantageous to make the arm support rigid whereby an especially precise guiding of the motor saw will be assured.

In order to make sure that when guiding the motor saw, the lower arm will be supported in any direction to the same extent by the arm support, the latter is round and preferably somewhat elliptical while the largest inner diameter of the support is in a plane transverse to the plane of the guiding rail of the motor saw.

A comfortable guiding of the motor saw will also be assured by providing the central axis of the holding device approximately parallel to the plane of the guiding rail of the motor saw and preferably about rectangularly with regard to the longitudinal direction of the motor saw. If the central axis of the handle is approximately at a right angle to the central axis of the above mentioned passage while preferably intersecting the latter, the wrist will be under a very slight load only.

In order to assure that the lower arm is supported by a large surface of the arm support, the latter has an oval cross-section with the largest diameter of its opening located about parallel to the central axis of the passage.

The holding device according to the present invention is also suitable for working with the motor saw when using both hands. To this end, behind the front handle part there may be provided a further rear handle part. A very simple construction is obtained when the rear handle part is formed by the arm support. With such a design, it is possible selectively to work with one hand or with both hands.

For purposes of further improving the handling of the motor saw, the handle part and the arm support are provided on the top side of the motor saw, preferably extending in upward direction.

In order for realizing a favorable lever ratio to create a relatively great distance between the handle and the arm support, the handle may be provided at the front end of the driving unit of the motor saw whereas the arm support may be located at the rear end of the driving unit. A further advantageous development of the invention consists in that the handle and/or the arm support are mounted on the motor saw through the intervention of at least one bearing adapted to dampen oscillations or vibrations. In such an instance, the shaking or vibrating of the motor saw will not or only in a dampened condition be conveyed to the handle and the arm support so that it is possible to work for a longer period of time with one hand without encountering fatigue or health damages.

According to a still further development of the invention, the handle and the arm support are substantially rigidly connected to each other through the intervention of a beam which preferably is formed by a part of the housing, as for instance the cover for the driving unit. This beam is journalled on the driving unit through the intervention of bearings adapted to absorb vibrations. In this way, on one hand, a damping and, on the other hand, only a slight play of movement between the handle and the arm support on one hand and the motor saw on the other hand is obtained so that the motor saw, in spite of the fact that the handles are well dampened, can be guided in a safe manner. This is the case in particular when three vibration damping bearings are provided at the tips of an imaginary triangle, preferably a triangle with acute angles.

According to a preferred embodiment of the invention, two oscillation damping bearings are provided adjacent to each other and at a right angle with regard to the plane of the guiding rail, the third bearing preferably being provided therebehind in such a manner that a particularly high precision of the location of the guiding rail with regard to the handle and the arm support will be assured.

Favorable lever conditions are particularly obtained when the rear bearing in the longitudinal direction of the motor saw is in approximate alignment with the handle, when the rear position is provided directly below the rear holding or supporting part, when the two front bearings in the longitudinal direction of the motor saw are located behind the handle, and when one of the two front bearings in the longitudinal direction of the motor saw is in approximate alignment with the guiding rail therefor.

The precision with regard to the guiding of the motor saw during the operation of the latter can still further be improved by locating the main degree of freedom of at least one, preferably all of oscillation damping bearings in the longitudinal direction of the motor saw and preferably at a right angle to the motor shaft thereof so that, particularly with internal combustion engines, the motor vibrations will be clamped to a great extent.

A simple embodiment of the oscillation or vibration damping bearings consists in that the same include elastic damping sleeves the central axes of which preferably extend at a right angle to the guiding rail. Expediently, each oscillation damping bearing has two damping sleeves mounted on a mandrel so that a simple assembly will be obtained. The oscillation damping bearings may be arranged below the support in a protected manner, preferably in the cap-shaped support.

The holding device according to the invention may be arranged on motor saws with gasoline engines and also on motor saws equipped with an electric motor. Furthermore, it is possible to arrange the holding device from the very start as an integral part of the motor saw or later to equip the motor saw with such holding device while the holding device may be detachable from the motor saw as a unit.

In order to be able to control the various functions of the motor saw while the motor saw is being used, especially when working with one hand, it is advantageous to provide within the area of the handle, especially the front handle, at least one actuating member for stopping the motor saw, for controlling the gas supply, for a short circuit switch, for a chain lubricating device or the like. In this way, the operations inherent thereto can be carried out by the operators hand which grasps the handle. The arrangement may, for instance, be such that for one-hand and two-hand operation separate actuating elements are provided. Inasmuch as the oil control with modern motor saws is as a rule effected by an automatic chain lubrication, and since the short circuit switch is equally well within reach when arranged in the area of the front handle as well as with one with twohand operation, the arrangement may be such that only the gas control can be effected with two separate handles such as gas levers. The second gas lever may be arranged at the front or at the rear handle. It is, however, also possible to arrange all of the actuating members at a central location so that they can easily be actuated when the device is designed for one-hand or for twohand operation. Expediently, the actuating member is located at the lower end of the front handle. It is also possible to provide the actuating member at the upper end of the front handle and preferably to design the same in the form of a push button.

According to a further development of the invention, above or in front of the front handle there is provided a protective shield or plate so that the sliding off of the hand holding said handle into the saw chain will be safely prevented. The same object may, of course, also be realized by another protective device for instance a protective hood or a corresponding design of the front handle.

Referring now to the drawings in detail, the motor saw illustrated in FIGS. 1-3 comprises a non-illustrated driving unit in the form of a combustion engine or an electric motor which is arranged in a housing 1. A sword-shaped guiding rail 2 protrudes beyond the front side of said housing 1 and serves for guiding a saw chain 3, said saw chain being driven by the drive motor in housing 1. The longitudinal direction of the guiding rail 2 (double arrow 4) defines the longitudinal direction of the motor saw. The plane in which the center of gravity of the motor saw is located is indicated by the dot-dash line 5.

The top of the housing 1 is formed by a cap-shaped cover 6 which is somewhat smaller than the bottom view of the housing 1 and is concave in downward direction. The lower marginal area of cover 6 is in slightly spaced relationship located above the housing 1. The housing cover 6 serving as support for a front handle 7 and for an arm support 8 is, through the intervention of three vibration damping bearings 9-1 1, mounted on the top side of the housing 1. The three bearings 9-11 engage the tips of an imaginary triangle 12 which is indicated by dot-dash lines in FIG. 2 and has exclusively acute angles. This triangle is located in a plane which is parallel to the upper side of housing 1. In other words, the plane 13, which passes through the axes of all vibration damping bearings 9-11, rises at an incline with regard to the central plane 14 of the guiding rail 2 (FIG. 1) which central plane is perpendicular to the guiding rail 2. This incline is such that the two planes 13 and 14 intersect at an acute angle which opens toward the free end of the guiding rail 2. In this way, the front vibration damping bearings 9,10 are with regard to the plane 14 located at a higher level or at a greater distance from plane 14 than the rear bearing 11.

The central axes 15, 16 of all vibration damping bearings 9-11 are at a right angle with regard to the guiding rail 2 and are thus parallel to each other. The two front vibration damping bearings 9, are located coaxially with regard to each other and adjacent to each other. The central plane 17, which is parallel to the above mentioned plane 5 and pertains to one of the two front bearings, namely the vibration damping bearing 10, is located in the central plane 18 of guiding rail 2, which central plane 18 is parallel to the plane of said guiding rail 2. Guiding rail 2 is at a right angle to its longitudinal central plane 18 eccentrically offset with regard to the driving unit in housing 1, while the vibration damping bearing 9, which is coaxial with regard to the vibration damping bearing 10, is, relative to the bearing 10, provided on the other side of plane 5. The spacing between the bearing 9 and said plane 5 is, however, slightly greater than the spacing of the bearing 10 from plane 5. The corresponding central plane of the rear bearing 11 is located in plane 5. The mean distance of the two bearings 9, 10 adjacently located with regard to each other is less than the corresponding mean distance of each of these bearings with regard to the rear vibration damping bearing 11. The front bearings 9, 10 have a greater distance from the front side 19 of the driving unit in housing 1 than the rear vibration damping bearing has from the back side 20 of said driving unit.

Each vibration damping bearing 9, 10, 11, has two damping sleeves 21 which flare conically and are coaxial. These sleeves 21, which are of a rubber elastic material, are arranged on a common mandrel 22 and have clamped therebetween a plate 23 which is not in engagement with the mandrel 22 but contacts only the sleeve 21. The ends of the mandrel 22 are passed through two plates 24 which are located at those end faces of the two damping sleeves 21 which face away from each other. The intermediate plate 23 which is at a right angle to the axes 15 and 16 of the bearing preferably forms one piece with the inner side of the housing cover 6, whereas the two plates 24 which are parallel to plate 23 are connected to the upper side of housing 1, for instance by forming one piece therewith. However, it is also possible to provide the plates 24 on cover 6 and to provide the plate 23 on housing 1.

In view of the design of the bearings 9 to 11 as described above, the main degree of freedom from the damping movement of said bearings is located parallel to the longitudinal central plane 18 of the guiding rail 2. When a load acts in a direction perpendicularly with regard to the central plane 18 of the guiding rail 2 under which circumstances the damping sleeve 21 are under considerable pressure, an extremely slight movability only is obtained.

Approximately in the middle between the axis 15 of the two front bearings 9, 10 and the front side 19 of the driving unit 1, the handle 7 is connected to the top of the cover 6. This handle 7 is, in the embodiment shown in the drawing, formed by a pipe 25 which is covered by a cover 26 of elastic material, said cover may have a corrugated surface. The central axis 27 of said tube 25, at least that portion of the central axis 27 which pertains to the lower section of the handle 7, is located in the plane of gravity 5 of the motor saw. As shown in FIG. 1, the central axis 27 together with the longitudinal central plane 14 defines an angle which is slightly greater than and opens toward the front.

Directly above the rear bearing 1 1 and symmetrically to the central plane thereof, which extends at a right angle to the axis 16, the upper side of the housing cover 6 is provided with a connecting flange formed by a protrusion 28. This protrusion is intended for connecting the rear handle 8 designed as arm support. The arm support 8 is formed by a bent ring which is detachably connected to flange 28 for instance by means of a screw 29. Ring 8, similar to handle 7, is formed by a pipe with a cover and has a cross section the circumference of which corresponds to the handle 7 so that ring 8 may at any desired area be grasped by the fingers of a hand as firmly as is the case with the handle 7. The cross section of ring 8 is, however, oval so that the ring has a relatively large inner surface which points to its center and defines the opening 30. The shape of ring 8 is approximately elliptical while its shorter diameter is approximately rectangular with regard to the plane 13. The central axis 32 of ring 8 or the opening 30 formed thereby extends parallel to the plane 13 and is located in the plane of gravity 5 so that the central axis 32 intersects the central axis 27 of the front handle 7 or is in alignment therewith. In view of the described design, the central plane 33 of ring 8 which is at a right angle with regard to axis 32 forms with plane 14 an angle which opens toward the front and which is slightly greater than 90 and is also greater than the corresponding angle between the central axis 27 and plane 14. Thus, the axes 27, 32 when viewed in side view according to FIG. 1 define an angle which is slightly less than 90.

The lower end of handle 7 has that side thereof which faces away from the guiding rail 2 provided with a pivotable actuating lever 34. By means of lever 34 it is possible to effect the gas control of the driving engine of the motor saw with that hand which holds the handle 7. Furthermore, the front side of housing cover 6 is provided with an upwardly pointing protective shield 35 which when viewed from the side according to FIG. 1 is angularly shaped. Shield 35 is located in front of the handle 7 and above the guiding rail 2.

The free width of ring 8 is so selected that it will just permit the passage of a hand or a fist. in order to operate with the motor saw according to the invention, one hand passes from the rear through the opening 31) of ring 8 and grasps the handle 7 so that ring 3 will surround the lower arm of the operator behind the wrist and in this way will furnish a support of the motor saw behind the handle 7. ln this way, the handling and working of the motor saw with one hand only will be possible.

According to the embodiment illustrated in FIGS. 4 to 6, the holding members 711, 8a are arranged directly on the upper side of the housing lla of the driving unit without the interposition of vibration damping bearings. The arm support 8a is, in its position for one-hand operation, according to FIG. 4, rearwardly inclined in such a way that its central plane 33a together with the central axis 27a of the front handle 7a (when viewed from the side according to FIG. 4) defines an upwardly opening acute angle. This means that the central plane 33a together with the central plane 14a of the guiding rail 2a, in other words, with the longitudinal direction (arrow 4) of the motor saw when viewed from the side according to FIG. 4 defines an upwardly opening angle considerably in excess of 90. In view of this inclined position of the arm support 811, a particularly large surface support for the lower arm of the operator will be assured. The upper half of the arm support 8a is surrounded by a thick layer, hose-like cushioning or upholstering 36 which may consist of soft rubber, foam rubber material or the like. In view of this cushioning 36, it will be assured that the arm support at least over half of its circumference is in an uninterrupted manner supporting the lower arm of the operator and, more specifically, substantially independently of the thickness of said lower arm.

As will be seen from FIGS. 4 to 6, the arm support 8a is pivotable about an axis 29a which is rectangular to the plane of the guiding rail 2a while the pivot axis 29a is located in the central plane 33a and directly at the upper side of housing la. As a result thereof, the arm support 8a can be pivoted toward the rear about the pivot axis 29a into the position shown in FIG. 5. In this way, the distance between the upper section of the support 8a and the front handle 7a will be increased so that when two-hand operation of the motor saw is provided during which the handle 7a is grasped with one hand and the support 8a is grasped with the other hand, particularly favorable lever conditions will be realized. The arm support 8a may in any position be arrested relative to the housing 1a by any standard arresting position not shown in the drawing.

The arm support 8a may also be pivotally mounted on housing 1a for pivoting about an axis which is parallel to the plane of the guiding rail 2a and preferably intersecting its central axis 32a at a right angle. In this connection, it is advantageous to journal the pivot bolt forming the pivot axis 29a over its central region in a corresponding bearing 28a so that the arm support 8a will in the manner of a universal joint be journalled on the top side of the housing 1a. By pivoting the arm support 8a about the bearing 280 into its position shown in FIG. 6 in which the central plane 33a is located in the longitudinal direction of the motor saw, the arm support 8a can be grasped by the second hand at its side which faces away from the front handle 7a, at a relatively great distance from the front handle 7a so that likewise favorable lever conditions are obtained. Expediently, the arm support 8a may in any desired pivoted position be arrested relative to the bearing 28a and housing 1a.

FIGS. 4 and 7 respectively illustrate in view and top view an advantageous embodiment for the front handle 7a. The handle 70 has a lower shank portion 26a which is formed by an elastic cover and which for purposes of obtaining a high friction has its circumference provided with adjacent groove-like depressions or corrugations so that annular beads arranged one above the other are formed. The upper end of the shank portion 26 is equipped with a knob 37 protruding beyond the circumference of the shank. The knob 37 has three starlike-shaped protrusions or tongues 38 two of which are at a right angle to the guiding rail 2a, 2b and are in alignment with each other, whereas the third extension or tongue points forwardly in the direction toward the free end of the guiding rail 2a, 2b. By means of the knob 37, the hand grasping the handle 7a is prevented from accidentally slipping in upward direction.

The upper end of the front handle has an actuating knob 340 which is located in the axis 27a of handle 7a and is adapted to be moved downwardly against the thrust of a spring. The actuating knob 34a may be operatively connected to the carburetor and/or a short circuit switch in the ignition circuit of the driving machine, so that by actuation of the actuating knob 34a, the speed of the motor may be adjusted or the motor may be turned off. The actuating knob 34a can easily be actuated by the thumb of a hand grasping the handle 7a.

As will be seen from FIG. 7, also two or more arm supports 8b may be provided and arranged one behind the other when looking in the longitudinal direction of the saw chain. With the illustrated embodiment, each arm support 8b forms a yoke in such a way that when viewing in longitudinal direction of the motor saw, both arm supports 8b will form a passage for the arm which passage is closed over the circumference. It is also possible in the longitudinal direction of the motor saw to provide two completely closed rings according to FIGS. 3 and 6 or to provide other arm supports arranged one behind the other. As shown in FIG. 7, the two arm supports have their lower ends which are directed opposite to each other journalled on plates 28b on the top side of housing lb by means of bolts 29b in such a way that the two arm supports 8b can be shifted from their position for one-hand operation according to FIG. 7, toward the rear into a position for two-hand operation.

The invention may also be applied in a simple manner to already existing motor saws by connecting thereto a corresponding arm support or ring. In such an instance, the holding device according to the invention is formed merely by an arm support connectable to a motor saw which arm support has a supporting surface for the arm of the operator. The passage for the arm at the rear arm support may also be designed in the manner of a hose.

Between the front holding member and the arm support there may be provided a particularly rigid connection 39 indicated in FIG. 4 which expediently is detachably connected in the upper range of the holding member 7a and the upper range of the arm support 8a so that it will not interfere. The connection established for instance by a longitudinal rod 39, which may also be provided with the design of FIG. 1 greatly increases the rigidity of the holding members 7a, 8a, and may be grasped by hand for a more comfortable carrying of the motor saw, inasmuch as in this way a rigid supporting frame is formed.

It is, of course, to be understood that the present invention is, by no means, limited to the particular showing in the drawings but also comprises any modifications within the scope of the appended claims.

What is claimed is:

1. An arrangement for holding saws, especially motor driven chain saws having a motor housing and a saw rail projecting from one end of the housing; at leastone hand graspable handle connected to the housing near the rail end thereof, and arcuate support means connected to the housing in spaced relation to said handle and adapted for supporting engagement with the lower arm simultaneously during grasping of said handle, said arcuate support means at least in part surrounding the lower arm kept from passing entirely therethrough to assure both hand and arm support during saw operation both below and above arm level work positioning thereof, said support means defining a passage only for receiving the arm therein and being spaced from said handle, the axis of said passage extending in the direction of the length of said rail and being substantially in the plane of said handle, said support means being in the form of a substantially rigid ring.

2. An arrangement according to claim 1, in which the central axis of said handle extends near the center of gravity of said motor.

3. An arrangement according to claim 1, in which the ring has a downwardly facing inside surface adapted to engage the top of the lower arm, said surface being substantially elliptical with the greater width extending transversely to the plane of the said rail.

4. An arrangement according to claim 1, in which the central axis of said handle is substantially parallel to the plane of said rail and substantially at right angles to the longitudinal direction of said housing, said central axis of said handle being near the axis of said ring and substantially at right angles thereto.

5. An arrangement according to claim 2, in which said surface on the inside of the ring is oval in cross sectional slope with the greater dimension thereof substantially parallel to the axis of said ring.

6. An arrangement according to claim 2, in which said surface on the inside of the ring is hose shaped.

7. An arrangement according to claim 1, in which said ring is supported on said housing for pivotal movement thereon in the fore and aft direction about a first axis substantially at right angles to the plane of said rail and for rotary movement about a second axis parallel to the plane of said rail, said first and second axes intersecting at a right angle.

8. An arrangement according to claim 1, in which said handle and support means are on top of said housing with said handle near the rail end of said housing and said support means near the other end of said housing.

9. An arrangement according to claim 8, which includes vibration damping means interposed between at least one of said handle and support means and said housing.

10. An arrangement according to claim 9, which in- I i said single damping element is substantially directly beneath said support means.

12. An arrangement according to claim 10, in which said pair of damping elements are disposed on the opposite side of said handle from said rail end of said housing and one thereof is substantially in the plane of said rail.

13. An arrangement according to claim 10, in which the principal direction of freedom of said damping elements is substantially parallel to the plane of said rail.

14. An arrangement according to claim 10, in which each damping element comprises a pair of elastic sleeves in coaxial relation on an axis perpendicular to the plane of said rail, and a mandrel common to each said pair of sleeves.

15. An arrangement according to claim 14, in which said rigid member is concave toward said housing so as to serve as a cap for the housing, said damping elements being disposed in the space between the bottom of said member and the top of said housing. 

1. An arrangement for holding saws, especially motor driven chain saws having a motor housing and a saw rail projecting from one end of the housing; at least one hand graspable handle connected to the housing near the rail end thereof, and arcuate support means connected to the housing in spaced relation to said handle and adapted for supporting engagement with the lower arm simultaneously during grasping of said handle, said arcuate support means at least in part surrounding the lower arm kept from passing entirely therethrough to assure both hand and arm support during saw operation both below and above arm level work positioning thereof, said support means defining a passage only for receiving the arm therein and being spaced from said handle, the axis of said passage extending in the direction of the length of said rail and being substantially in the plane of said handle, said support means being in the form of a substantially rigid ring.
 2. An arrangement according to claim 1, in which the central axis of said handle extends near the center of gravity of said motor.
 3. An arrangement according to claim 1, in which the ring has a downwardly facing inside surface adapted to engage the top of the lower arm, said surface being substantially elliptical with the greater width extending transversely to the plane of the said rail.
 4. An arrangement according to claim 1, in which the central axis of said handle is substantially parallel to the plane of said rail and substantially at right angles to the longitudinal direction of said housing, said central axis of said handle being near the axis of said ring and substantially at right angles thereto.
 5. An arrangement according to claim 2, in which said surface on the inside of the ring is oval in cross sectional slope with the greater dimension thereof substantially parallel to the axis of said ring.
 6. An arrangement according to claim 2, in which said surface on the inside of the ring is hose shaped.
 7. An arrangement according to claim 1, in which said ring is supported on said housing for pivotal movement thereon in the fore and aft direction about a first axis substantially at right angles to the plane of said rail and for rotary movement about a second axis parallel to the plane of said rail, said first and second axes intersecting at a right angle.
 8. An arrangement according to claim 1, in which said handle and support means are on top of said housing with said handle near the rail end of said housing and said support means near the other end of said housing.
 9. An arrangement according to claim 8, which includes vibration damping means interposed between at least one of said handle and support means and said housing.
 10. An arrangement according to claim 9, which includes a rigid member to which said handle and support means are fixed, and resilient vibration damping means connecting said rigid member to said housing, saiD vibration damping means comprising a pair of laterally spaced damping elements near the rail end of said member and a single damping element near the opposite end of said member and near the central plane of said housing, said damping elements being disposed at the vertices of an acute angle triangle.
 11. An arrangement according to claim 10, in which said single damping element is substantially directly beneath said support means.
 12. An arrangement according to claim 10, in which said pair of damping elements are disposed on the opposite side of said handle from said rail end of said housing and one thereof is substantially in the plane of said rail.
 13. An arrangement according to claim 10, in which the principal direction of freedom of said damping elements is substantially parallel to the plane of said rail.
 14. An arrangement according to claim 10, in which each damping element comprises a pair of elastic sleeves in coaxial relation on an axis perpendicular to the plane of said rail, and a mandrel common to each said pair of sleeves.
 15. An arrangement according to claim 14, in which said rigid member is concave toward said housing so as to serve as a cap for the housing, said damping elements being disposed in the space between the bottom of said member and the top of said housing. 